Develop Reference

MVC reusing model

I have an MVC Web Application which uses a form to get a postal code from the user, which then queries an external web service and returns a list of addresses to the view.
I had a previous issue whereby my model was static, therefore the data was being displayed to users on other clients, rather than being specific to each user. I have now got it so each individual user can query and get their list of addresses on the view (which isn't visible to anyone else) however, when the user refreshes the page or goes back, the data is lost.
I have some code on the page refresh which checks if the data is there and won't take the user to the start of the form, however on page refresh the model returns to null, hence it will always take them back to the beginning.
Any ideas? I ideally want to be able to use the data multiple times for the current user, but if they refresh and are say 90% through the form, they will lose the whole data. It seems like it should be easy but all of the examples I have tried haven't worked for my particular scenario.
Controller:
public class AssistedController : Controller
{
// GET: Assisted
AddressList model;
public ActionResult Index()
{
return View(model);
}
[HttpPost]
public ActionResult GetAddresses(string postcode)
{
model = new AddressList();
if (postcode == null || postcode == "")
{
return RedirectToAction("/Index/");
}
//call enviroweb web service
AddressWeb ew = new AddressWeb();
//extract address values from the XML returned from web service
XmlNode xml = ew.GetAddress(", , , , " + postcode);
foreach (XmlElement addressInfo in xml)
{
foreach (XmlElement teset in addressInfo["Addresses"])
{
//add each address item found to the list
model.listone.Add(new AddressResults {
FullAddress = teset["fulladdress"].InnerText,
Lat = teset["Lat"].InnerText,
Lon = teset["Long"].InnerText,
addLine1 = teset["addline1"].InnerText,
addLine2 = teset["addline2"].InnerText,
addLine3 = teset["addline3"].InnerText,
addLine4 = teset["addline4"].InnerText,
Town = teset["Town"].InnerText,
postcode = teset["postcode"].InnerText,
Ownership = teset["Ownership"].InnerText,
WeekNumber = teset["WeekNumber"].InnerText
});
}
}
//return the list and model back to the index view
return View("Index", model);
}
View:
<!--Use the model to return the data-->
#model AddressSearch.Models.AddressList
#{
ViewBag.Title = "Index";
Layout = "~/Views/Shared/_Layout.cshtml";
}
#if (Model == null)
{
}
else
{
if (Model.listone.Count != 0)
{
//this section returns the items as options in the select if the list count is greater than 0.
foreach (var test in Model.listone)
{
<option value="#test.FullAddress">#test.FullAddress</option>
}
}
}
Model:
public class AddressList
{
public List<AddressResults> listone = new List<AddressResults>();
}

TempData in ASP.NET MVC can be used to store temporary data which can be used in the subsequent request. TempData will be cleared out after the completion of a subsequent request.
public class AssistedController : Controller
{
// GET: Assisted
AddressList model;
public ActionResult Index()
{
if (TemData.ContainsKey("address"))
{
model = TempData["address"] as AddressList;
}
return View(model);
}
[HttpPost]
public ActionResult GetAddresses(string postcode)
{
model = new AddressList();
if (postcode == null || postcode == "")
{
return RedirectToAction("/Index/");
}
if (TemData.ContainsKey("address"))
{
model = TempData["address"] as AddressList;
return View(model);
}
//call enviroweb web service
AddressWeb ew = new AddressWeb();
//extract address values from the XML returned from web service
XmlNode xml = ew.GetAddress(", , , , " + postcode);
foreach (XmlElement addressInfo in xml)
{
foreach (XmlElement teset in addressInfo["Addresses"])
{
//add each address item found to the list
model.listone.Add(new AddressResults
{
FullAddress = teset["fulladdress"].InnerText,
Lat = teset["Lat"].InnerText,
Lon = teset["Long"].InnerText,
addLine1 = teset["addline1"].InnerText,
addLine2 = teset["addline2"].InnerText,
addLine3 = teset["addline3"].InnerText,
addLine4 = teset["addline4"].InnerText,
Town = teset["Town"].InnerText,
postcode = teset["postcode"].InnerText,
Ownership = teset["Ownership"].InnerText,
WeekNumber = teset["WeekNumber"].InnerText
});
}
}
TempData["address"] = model;
//return the list and model back to the index view
return View("Index", model);
}
}
Refer this link to how to use

MVC data passing in view

I am making my MVC application. I open my view with predefined parameters like this:
return RedirectToAction("PickGroupForHomework", "Account", new {subject_id = id, qty=model.qty });
And this works fine, the data subject_id and qty are passed correctly. However, my view PickGroupForHomework contains a form to fill, which is then validated. If the input is not valid, the window simply should reload with the data subject_id and qty as defined in previous view. I do this in such way:
public ActionResult PickGroupForHomework(PickGroupForHomeworkViewModel model)
{
ClassDeclarationsDBEntities2 entities = new ClassDeclarationsDBEntities2();
model.groups = entities.Groups.ToList();
model.users = entities.Users.ToList();
int id = model.subject_id;
var subj = entities.Subjects
.Where(b => b.class_id == model.subject_id)
.FirstOrDefault();
if (subj != null)
{
model.subject_name = subj.name;
}
if (ModelState.IsValid)
{
}
else
{
return View(model);
}
return View(model);
}
But the resulting URL does not contain the data I need, but just a plain view. How do I do it right?

In order for you wep app to work, you will need two actions, one to set your model up for the View and another to actually do the work to post and save your data:
public ActionResult PickGroupForHomework(int subject_id, int qty)
{
//Initialize your model here. Below is just an example.
ClassDeclarationsDBEntities2 entities = new ClassDeclarationsDBEntities2();
PickGroupForHomeworkViewModel model = new PickGroupForHomeworkViewModel();
model.groups = entities.Groups.ToList();
model.users = entities.Users.ToList();
model.subject_id = subject_id;
model.qty = qty;
return View("PickGroupForHomework", model);
}
[HttpPost]
public ActionResult PickGroupForHomework(PickGroupForHomeworkViewModel model)
{
ClassDeclarationsDBEntities2 entities = new ClassDeclarationsDBEntities2();
int id = model.subject_id;
var subj = entities.Subjects
.Where(b => b.class_id == model.subject_id)
.FirstOrDefault();
if (subj != null)
{
model.subject_name = subj.name;
}
if (ModelState.IsValid)
{
//Save to database
[code goes here]
//return to a View to show your results
return View("[Your view to see the results]")
}
//Model Validation did not pass
//or exception occurred go back to View
return View(model);
}

MVC setting up Html.DropdownList on ModelState.IsValid = false

This is something that has always puzzled me as to the best way round, while keeping maintainable code. The below code sets up a list of months and years for a payment gateway form, before assigning these to a variable of type List<SelectListItem>.
Intial Action
PayNowViewModel paymentGateway = new PayNowViewModel();
List<SelectListItem> paymentGatewayMonthsList = new List<SelectListItem>();
List<SelectListItem> paymentGatewayYearsList = new List<SelectListItem>();
for (int i = 1; i <= 12; i++)
{
SelectListItem selectListItem = new SelectListItem();
selectListItem.Value = i.ToString();
selectListItem.Text = i.ToString("00");
paymentGatewayMonthsList.Add(selectListItem);
}
int year = DateTime.Now.Year;
for (int i = year; i <= year + 10; i++)
{
SelectListItem selectListItem = new SelectListItem();
selectListItem.Value = i.ToString();
selectListItem.Text = i.ToString("00");
paymentGatewayYearsList.Add(selectListItem);
}
paymentGateway.ExpiryMonth = paymentGatewayMonthsList;
paymentGateway.ExpiryYear = paymentGatewayYearsList;
return View(paymentGateway);
It's a fair bit of code, and I find myself repeating this code, in similar formats to re-setup the dropdown lists options should the ModelState.IsValid be false and I want to return back to the view for the user to correct there mistakes.
HttpPost Action - Code
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult ConfirmPayment(PayNowViewModel paymentGatewayForm, FormCollection form)
{
if (ModelState.IsValid)
{
// Post processing actions...
return View();
}
else
{
for (int i = 1; i <= 12; i++)
{
SelectListItem selectListItem = new SelectListItem();
selectListItem.Value = i.ToString();
selectListItem.Text = i.ToString("00");
paymentGatewayMonthsList.Add(selectListItem);
}
int year = DateTime.Now.Year;
for (int i = year; i <= year + 10; i++)
{
SelectListItem selectListItem = new SelectListItem();
selectListItem.Value = i.ToString();
selectListItem.Text = i.ToString("00");
paymentGatewayYearsList.Add(selectListItem);
}
form.ExpiryMonth = paymentGatewayMonthsList;
form.ExpiryYear = paymentGatewayYearsList;
return View("MakePayment", form);
}
}
What's the best way to centralise this dropdown setup code so its only in one place? At present you'll see a large proportion (the for loops), is exactly repeated twice. A base controller with function? Or is it better to re-setup like the above?
Any advice appreciated!
Mike.

Add a private method to your controller (the following code assumes your ExpiryMonth and ExpiryYear properties are IEnumerable<SelectListItem> which is all that the DropDownListFor() method requires)
private void ConfigureViewModel(PayNowViewModel model)
{
model.ExpiryMonth = Enumerable.Range(1, 12).Select(m => new SelectListItem
{
Value = m.ToString(),
Text = m.ToString("00")
});
model.ExpiryYear = Enumerable.Range(DateTime.Today.Year, 10).Select(y => new SelectListItem
{
Value = y.ToString(),
Text = y.ToString("00")
});
}
and then in the GET method
public ActionResult ConfirmPayment()
{
PayNowViewModel model = new PayNowViewModel();
ConfigureViewModel(model);
return View(model);
}
and in the POST method
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult ConfirmPayment(PayNowViewModel model)
{
if (!ModelState.IsValid)
{
ConfigureViewModel(model);
return View(model);
}
.... // save and redirect (should not be returning the view here)
}

If the set of your dropdown options is fixed (or recompilation is OK after the potential options change), you can use an enum to store your options.
public enum Month {
// if the dropdown is not required, add default value 0
Optional = 0,
[Display(Name = #"Month_January")]
January = 1,
[Display(Name = #"Month_February")]
February = 2,
// etc ..
}
To render this as a dropdown use an EditorTemplate Enum.cshtml:
#model Enum
#{
var enumType = ViewData.ModelMetadata.ModelType;
var allValues = Enum.GetValues(enumType).Cast<object>().ToSelectList(Model);
// read any attributes like [Required] from ViewData and ModelMetadata ...
var attributes = new Dictionary<string, object>();
}
#Html.DropDownListFor(m => m, allValues, attributes)
The ToSelectList extension method loops over all enum values and converts them to SelectListItems:
public static IList<SelectListItem> ToSelectList<T>(this IEnumerable<T> list) {
return ToSelectList<T>(list, list.FirstOrDefault());
}
public static IList<SelectListItem> ToSelectList<T>(this IEnumerable<T> list, T selectedItem) {
var items = new List<SelectListItem>();
var displayAttributeType = typeof(DisplayAttribute);
foreach (var item in list) {
string displayName;
// multi-language:
// assume item is an enum value
var field = item.GetType().GetField(item.ToString());
try {
// read [Display(Name = #"someKey")] attribute
var attrs = (DisplayAttribute)field.GetCustomAttributes(displayAttributeType, false).First();
// lookup translation for someKey in the Resource file
displayName = Resources.ResourceManager.GetString(attrs.Name);
} catch {
// no attribute -> display enum value name
displayName = item.ToString();
}
// keep selected value after postback:
// assume selectedItem is the Model passed from MVC
var isSelected = false;
if (selectedItem != null) {
isSelected = (selectedItem.ToString() == item.ToString());
}
items.Add(new SelectListItem {
Selected = isSelected,
Text = displayName,
Value = item.ToString()
});
}
return items;
}
To support multiple languages, add translations for the display name keys, e.g. "Month_January", to the Resource file.
Now that the setup code has been abstracted away using some reflection magic, creating a new viewmodel is a breeze :>
public class PayNowViewModel {
// SelectListItems are only generated if this gets rendered
public Month ExpiryMonth { get; set; }
}
// Intial Action
var paymentGateway = new PayNowViewModel();
return View(paymentGateway);
// Razor View: call the EditorTemplate
#Html.EditorFor(m => m.ExpiryMonth)
Note that in the EditorTemplate, Model is passed as the selected item to ToSelectList. After postback, Model will hold the currently selected value. Therefore it stays selected, even if you just return the model after an error in the controller:
// HttpPost Action
if (!ModelState.IsValid) {
return View("MakePayment", paymentGatewayForm);
}
Took us some time to come up with this solution, credits go to the Saratiba team.

passing data between controller methods

I'm creating asp.net mvc 5 application. in this application I have faced to problem passing data between controller methods.
Here the scenario step by step
I'm getting IEnumerable dataset to Create_Brochure method like this
public ActionResult Create_Brochure(IEnumerable<ProductsPropertiesVM> model)
{
IEnumerable<BrochureTemplateProperties> sample = model.Where....
return View(sample);
}
Then I need to save that IEnumerable<ProductsPropertiesVM> model to another IEnumerable object and use that in Create_Brochure_PDF() method
public ActionResult Create_Brochure_PDF()
{
IEnumerable<BrochureTemplateProperties> samplePDF = modelPDF....
return View(samplePDF);
}
for that I'did bit R&D part and came up solution with Sessions , Here the tutorial I followed
So I changed my code like this
but seems I'm having compile time errors though I followed exact as tutorial
1st controller method
[HttpPost]
[ValidateInput(false)]
public ActionResult Create_Brochure(IEnumerable<ProductsPropertiesVM> model)
{
IEnumerable<ProductsPropertiesVM> modelPDF = new IEnumerable<ProductsPropertiesVM>();
modelPDF = model;
IEnumerable<BrochureTemplateProperties> sample = model.Where(y => y.IsChecked)
.Select(y => new BrochureTemplateProperties
{
Property_ID = y.Property_ID,
IsChecked = y.IsChecked,
Property_Title = y.Property_Title,
Property_Value = y.Property_Value
});
TempData["TemplateData"] = modelPDF;
return View(sample);
}
2nd controller method
public ActionResult Create_Brochure_PDF()
{
IEnumerable<ProductsPropertiesVM> modelPDF = TempData["TemplateData"] as IEnumerable<ProductsPropertiesVM>;
IEnumerable<BrochureTemplateProperties> samplePDF = modelPDF.Where(y => y.IsChecked)
.Select(y => new BrochureTemplateProperties
{
Property_ID = y.Property_ID,
IsChecked = y.IsChecked,
Property_Title = y.Property_Title,
Property_Value = y.Property_Value
});
return View(samplePDF);
}

You can not instantiate interface..!
Replace
IEnumerable<ProductsPropertiesVM> modelPDF = new IEnumerable<ProductsPropertiesVM>();
modelPDF = model;
With
IEnumerable<ProductsPropertiesVM> modelPDF = model;
inside your Create_Brochure method.

capturing value of parameter

I really need your help on this guys I am stuck and not sure where to start the fix. So i have this form where the user can select a case and parties. I am supposed save and pass along the values of the selected items. I was able to save the case selections but i am having trouble saving the selected party. Here is my code snippets regarding gathering data and saving them.
CONTROLLER:
[HttpPost]
[ValidateInput(false)]
public ActionResult Create(VisitViewModel viewModel, Guid[] associatedCasesSelected, Guid[] selectedParties)
{
if (!ModelState.IsValid)
{
viewModel.Time = _timeEntryHelper.Value;
AddLookupsToViewModel(viewModel);
return View(viewModel);
}
var visitEntry = Mapper.Map<VisitViewModel, VisitEntry>(viewModel);
visitEntry.VisitDate = _timeEntryHelper.AddTimeToDate(visitEntry.VisitDate);
visitEntry.UserId = _currentUser.UserId;
visitEntry.OfficeId = _currentUser.OfficeId;
try
{
_visitEntryService.Create(visitEntry, associatedCasesSelected, selectedParties);
this.FlashInfo(string.Format(Message.ConfirmationMessageCreate, Resources.Entities.Visit.EntityName));
}
catch (RulesException ex)
{
ex.CopyTo(ModelState);
}
if (ModelState.IsValid)
return RedirectToAction("Edit", "Case", new { caseId = viewModel.CaseId });
AddLookupsToViewModel(viewModel);
return View(viewModel);
}
VisitEntryService:
public void Create(VisitEntry visitEntry,IList<Guid>caseIds, IList<Guid>partyIds )
{
EnsureValid(visitEntry);
_visitEntryRepository.Save(visitEntry);
caseIds = AddCurrentCaseToCases(visitEntry.CaseId, caseIds,partyIds);
foreach (var caseId in caseIds.Distinct())
{
var visit = new Visit {CaseId = caseId, VisitEntryId = visitEntry.VisitEntryId};
_visitService.Create(visit);
}
}
VisitEntryRepository:
public void Save(VisitEntry visitEntry)
{
if (visitEntry.VisitEntryId == Guid.Empty)
{
visitEntry.VisitEntryId = Guid.NewGuid();
visitEntry.DateCreated = DateTime.Now;
DataContext.VisitEntries.InsertOnSubmit(visitEntry);
}
else
{
var currentVisitEntry = Get(visitEntry.VisitEntryId);
if (currentVisitEntry == null) throw RepositoryExceptionFactory.Create("VisitEntry", "VisitEntryId");
currentVisitEntry.DateModified = DateTime.Now;
currentVisitEntry.VisitDate = visitEntry.VisitDate;
currentVisitEntry.VisitType =
DataContext.VisitTypes.SingleOrDefault(vt => vt.VisitTypeId == visitEntry.VisitTypeId);
currentVisitEntry.Note = visitEntry.Note;
}
DataContext.SubmitChanges();
}
I am not sure how to get this to save the selected party as it is saving the case information and selected case. Thanks for any feedback!

The save call is a bit earlier so your changes made after your fire SubmitChanges, move the SubmitChanges to the end you should good to go I believe
UPDATE
what I mean is change code like following and see if that helps
CONTROLLER:
[HttpPost]
[ValidateInput(false)]
public ActionResult Create(VisitViewModel viewModel, Guid[] associatedCasesSelected, Guid[] selectedParties)
{
if (!ModelState.IsValid)
{
viewModel.Time = _timeEntryHelper.Value;
AddLookupsToViewModel(viewModel);
return View(viewModel);
}
var visitEntry = Mapper.Map<VisitViewModel, VisitEntry>(viewModel);
visitEntry.VisitDate = _timeEntryHelper.AddTimeToDate(visitEntry.VisitDate);
visitEntry.UserId = _currentUser.UserId;
visitEntry.OfficeId = _currentUser.OfficeId;
try
{
_visitEntryService.Create(visitEntry, associatedCasesSelected, selectedParties);
this.FlashInfo(string.Format(Message.ConfirmationMessageCreate, Resources.Entities.Visit.EntityName));
DataContext.SubmitChanges();
}
catch (RulesException ex)
{
ex.CopyTo(ModelState);
}
if (ModelState.IsValid)
return RedirectToAction("Edit", "Case", new { caseId = viewModel.CaseId });
AddLookupsToViewModel(viewModel);
return View(viewModel);
}
VisitEntryRepository:
public void Save(VisitEntry visitEntry)
{
if (visitEntry.VisitEntryId == Guid.Empty)
{
visitEntry.VisitEntryId = Guid.NewGuid();
visitEntry.DateCreated = DateTime.Now;
DataContext.VisitEntries.InsertOnSubmit(visitEntry);
}
else
{
var currentVisitEntry = Get(visitEntry.VisitEntryId);
if (currentVisitEntry == null) throw RepositoryExceptionFactory.Create("VisitEntry", "VisitEntryId");
currentVisitEntry.DateModified = DateTime.Now;
currentVisitEntry.VisitDate = visitEntry.VisitDate;
currentVisitEntry.VisitType =
DataContext.VisitTypes.SingleOrDefault(vt => vt.VisitTypeId == visitEntry.VisitTypeId);
currentVisitEntry.Note = visitEntry.Note;
}
}